Suffice it to say that the technology has drastically improved and, despite recent studies demonstrating its efficacy, current guidelines do not advocate for routine renal tumor biopsies. It is only recommended when non-RCC histology is suspected or patient is not a surgical candidate – basically when looking for a reason to not offer intervention.
Currently, CT imaging (axial cross-sectional imaging with contrast) is the standard of care evaluation for renal masses. We know that masses without contrast enhancement are likely to be benign. Evaluation requires 4 phases: non-contrast, corticomedullary phases, nephrogenic phase and delayed phase. Using this, we can pretty accurately assess renal masses – but it does not tell us about benign tumors or about the histology of malignant tumors.
- It does have high sensitivity and specificity for RCC
- Inaccurate for the identification of oncocytoma
1. mpMRI – as with prostate evaluation, this requires multiple phases (T1, T2, Diffusion Weight Imaging, Dynamic contrast enhancement)
- It has high sensitivity and specificity for renal masses (88-100% sensitivity, 83-93% specific)
- “Solid Renal masses: What the Numbers Tell Us” 1 – MRI is already the most effective tool available!
- MRI outperforms CT when differentiating oncocytoma from RCC – however, its still not perfect
- However, major limitation has been urologist inability and discomfort with interpreting these images – but if we order more regularly, it may actually be a better tool!
- There has been increasing use of contrast-enhanced ultrasound (CEUS) outside the United States – which has the benefit of being simple, short, and without radiation risk.
- It has some benefits over CT
- It is better at evaluating hypovascular areas through background suppression
- It also is able to better evaluate the enhancement of septations in complex cysts
- Better than CT at differentiating cyst from solid mass
- CEUS has been validated as a measure of Bosniak classification
- It has high sensitivity and specificity for malignant tumors (100% and 95%, respectively) – PPV 95% and NPV 100%
- This is a tool that warrants more research and attention!
- This is a new technology with limited data
- It specifically assesses vascular heterogeneity
- Most of the work in this technology has been focused on liver and lung pathology
- Preliminary pilot study demonstrates high sensitivity and specificity for malignant RCC, ccRCC and oncocytoma. Sens/specificity exceeded 90% for all of these2
4. Nuclear Medicine imaging
- Currently, the Technetium-99 Sestamibi scan (traditionally used by cardiologists and endocrine surgeons) may have a role in differentiating oncocytoma3, 4
- Two studies that assessed the efficacy in this space
- Not perfect, but distinguishes oncocytoma from RCC pretty well - 80-90% accurate for oncocytoma
Presented by: Krishnanath Gaitonde, University of Cincinnati, Cincinnati, Ohio, United States
1. Kang et al. AJR 2014.
2. Raman et al. Acad Rad. 2018
3. Gorin et al. 2015.
4. Tzortakakis et al. 2017.
Written By: Thenappan Chandrasekar, MD, Clinical Instructor, Thomas Jefferson University Twitter: @tchandra_uromd, @TjuUrology at the 38th Congress of the Society of International Urology - October 4- 7, 2018 - Seoul, South Korea